any of several species of slimy freshwater African fishes that comprise the family Mormyridae (order Mormyriformes). They are usually found in sluggish, muddy water. Mormyrids are soft-rayed bony fishes with abdominal pelvic fins, forked tail fins, small mouths and eyes, restricted gill openings, and small scales. They range from 9 to 50 cm (3.5 to about 20 inches) in length. Their brains are proportionately very large, comparable to that of humans in relation to body weight; enlarged areas of the brain indicate well-developed senses. A loosely attached bony plate on each side of the head covers a vesicle that communicates with the internal ear. Paired electric organs of mild power, present in the tail, set up a continuous electric field around the fish, acting as a sensory screen. Most mormyrids feed on small prey, aquatic vegetation, or organic debris.
Learn more about mormyr with a free trial on Britannica.com.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.